A websites protected by client certificate authentication is a highly secure, exclusive building that won't allow random people to walk in, even if they know the address. There will be two security checkpoints: at first checkpoint (like a standard HTTPS website), you have to show a valid photo ID (the server certificate) so you know the building is legitimate and safe to enter.
At the second checkpoint—unique to this building—the guard will only allow access if you also present a special VIP badge (the client certificate) that was issued to you by the building's trusted administrator. Only people with a valid VIP badge, issued by the recognized authority, and confirmed as authentic, are let through the door. This two-way check (mutual authentication) ensures only authorized guests (trusted clients with valid client certificates) can access the building’s inner offices (restricted web resources), providing much higher security than simple locks or passwords.
This is why monitoring websites behind client certificates is handled differently as site access is restricted to users or systems that present valid digital certificates during the SSL/TLS handshake.
What is client certificate authentication?
Client certificate authentication involves mutual SSL/TLS authentication, where both the server and client authenticate each other using digital certificates issued by trusted Certificate Authorities (CAs). During the handshake, after the server presents its certificate, it also requests the client to present its certificate. The server then validates the client's certificate to verify identity before continuing the secure session.
Why is it important to monitor websites behind client certificate?
Many sensitive or enterprise applications require client certificate authentication to ensure only authorized users are allowed access the service. Monitoring such websites or APIs demands that the monitoring tool itself present a valid client certificate; otherwise, access will be denied, and monitoring checks will fail.
How Site24x7 supports monitoring behind client certificates
Site24x7 allows users to configure client certificate authentication for website monitors that need to access resources protected by client certificates. This involves:
- Uploading a valid client certificate in PEM or PKCS#12 format along with the corresponding private key.
- Providing necessary passwords or passphrases to decrypt the certificate, if any.
- Specifying which domains or URLs require the client certificate during monitoring.
Site24x7 injects the client certificate into the SSL/TLS handshake during synthetic checks, enabling successful authentication and access.
Monitoring websites behind client certificate authentication using Site24x7
Site24x7 supports monitoring websites that require client certificate authentication. Here's a step-by-step guide on configuring a website monitor in Site24x7. While adding a monitor, you can upload the client certificate as a PKCS#12 file, for websites that require client certificate authentication.
Site24x7 will begin authenticating with the client certificate during monitoring, enabling access to the secured website for ongoing synthetic checks.
Key considerations
- On-Premise Poller: Essential for monitoring sites behind corporate firewalls or secure internal networks, enabling Site24x7 to conduct monitoring without exposing internal systems publicly.
- Certificate format: Upload only certificates in the PKCS#12 format, which includes both the public certificate and the corresponding private key required for authentication during SSL/TLS handshakes.
- Separate from SSL/TLS Certificate monitoring: Site24x7 also offers dedicated monitoring for server-side SSL/TLS certificates, which track the validity and expiration of server certificates. Client certificate authentication setup is distinct and focuses on client identity verification.
Benefits of client certificate monitoring with Site24x7
Uptime and performance-related metrics can be obtained for secured web applications. Authentication failures can be detected early to prevent access disruptions. Monitoring of services can be done from private or restricted environments without compromising security.
Key considerations for effective monitoring
- Ensure the client certificate is issued by a CA trusted by the target server and is not expired or revoked.
- Protect private keys used for authentication securely to prevent compromise.
- Keep a track of the certificate expiration dates; automate certificate renewal to avoid monitoring failures.
- Configure meaningful monitoring alerts for SSL handshake failures specific to client certificate issues, enabling quick root cause analysis.
- Client certificate authentication usually coexist with other mechanisms like IP whitelisting, firewalls, or token-based authentication for layered security.
Benefits of monitoring secured websites this way
- Enables uninterrupted monitoring of internal or partner portals with enhanced security requirements.
- Detects authentication failures proactively, preventing unexpected visibility gaps.
- Helps maintain compliance with organizational and regulatory security policies by ensuring only authorized traffic is monitored.
- Provides accurate synthetic monitoring results reflective of the real user experience for authenticated users.
In summary, monitoring websites behind client certificate authentication requires the monitoring tool to support mutual TLS by presenting valid client certificates during SSL handshakes. Delve deeper into the capabilities of our website monitoring tool and try signing up for a free trial.